Why is it important to talk about future probability?

When we talk about the future, we are often not 100% sure about what will happen. We make predictions, guesses, or talk about possibilities.

Learning to express different levels of certainty is very useful. It helps you:

• Share your predictions clearly.
• Understand other people’s opinions about the future.
• Sound more natural and fluent in English conversations.

How do we express future probability in English?

English uses several types of words and phrases to show how likely something is to happen in the future. We can use:

• Modal verbs: Words like will, may, might, 、および could.
• Adverbs: Words like certainly, probably, 、および unlikely.
• Adjectives and phrases: Expressions such as It’s likely that… または There’s a good chance….

Let’s look at these in more detail, from high probability to low probability.

Expressing High Probability (75-100%)

When you are very sure something will happen, or it’s almost certain, you can use these expressions:

• Will certainly / Certainly will: This shows a very high degree of certainty.
  • The sun will certainly rise tomorrow. (100%)
  • I will certainly finish my report by Friday. (Very high, almost 100%)
• Will probably / Probably will: This means you think it’s very likely, but not 100% sure.
  • It will probably rain later. (Around 75-90%)
  • They’ll probably arrive around 7 PM.
• May well / Might well / Could well: These suggest a strong possibility, often because there’s a good reason.
  • She may well get the job; she’s very qualified. (Around 75%)
  • The project could well be delayed due to bad weather.
• It’s (very) likely that…: This adjective phrase also shows high probability.
  • It’s very likely that prices will increase next year.
• I’m sure / I’m certain that…: These personal expressions show your strong belief.
  • I’m sure they’ll love the present.

Expressing Medium Probability (50%)

When you think something has a 50/50 chance of happening, or it’s simply possible, use these:

• May / Might / Could: These modal verbs indicate possibility without strong certainty. May is slightly more formal than might または could.
  • I may go to the party, but I haven’t decided yet. (50%)
  • They might visit us next summer.
  • It could snow tomorrow.
• It’s possible that…: This phrase directly states a possibility.
  • It’s possible that the meeting will be cancelled.
• There’s a (good) chance that…: This phrase suggests a reasonable possibility.
  • There’s a good chance that we’ll finish on time.

Expressing Low Probability (0-25%)

When you think something is unlikely to happen, or almost impossible, use these expressions:

• Probably won’t / Won’t probably (less common): This shows a low likelihood. The adverb probably usually comes before won’t.
  • I probably won’t have time to call you back today. (Around 10-25%)
  • They probably won’t agree with our proposal.
• It’s (very) unlikely that…: This phrase clearly states a low probability.
  • It’s very unlikely that I’ll win the lottery.
• Almost certainly won’t / Won’t almost certainly: This indicates a very low probability, close to 0%.
  • She almost certainly won’t accept that offer. (Very low, almost 0%)
• There’s no chance that…: This means it’s impossible.
  • There’s no chance that he’ll change his mind now. (0%)

例

• The new restaurant will certainly be popular.
• I’ll probably work from home tomorrow.
• She may well get a promotion next year.
• We might go to the beach if the weather is good.
• It could rain later, so take an umbrella.
• It’s possible that they’ll arrive late.
• There’s a good chance of snow this weekend.
• He probably won’t remember my name.
• It’s unlikely that the project will finish on schedule.
• They almost certainly won’t agree to those terms.

練習

スペイン語話者がよく犯す間違い

Spanish speakers sometimes make mistakes when expressing future probability due to direct translation or incorrect word order.

• Incorrect placement of probably: In English, probably usually comes between the modal verb and the main verb, or before won’t.
  • Incorrect: I will go probably.
  • Correct: I will probably go.
  • Correct: I probably won’t go.
  • Incorrect: I won’t probably go.
• Confusing may, might, 、および could: While often interchangeable for possibility, remember may well, might well, 、および could well suggest a stronger, more reasoned possibility.
  • I may go to the cinema. (Simple possibility)
  • I may well go to the cinema, as I have nothing else to do. (Stronger possibility with a reason)
• Using is possible instead of it’s possible: Remember to use the impersonal subject it.
  • Incorrect: Is possible that it rains.
  • Correct: It’s possible that it will rain.

よくある質問

What is the difference between ‘will probably’ and ‘may well’?

Will probably suggests a high likelihood based on general expectation or common sense, like It will probably be cold in winter. May well （または might well, could well) suggests a strong possibility often supported by a specific reason or evidence, for example, She may well get the promotion; she has the most experience.

Can I use ‘will’ for 100% certainty?

はい、, will can express 100% certainty when talking about facts or scheduled events, like The train will depart at 10 AM. However, when we add adverbs like certainly または probably, we are indicating a degree of certainty that is less than absolute fact.

Is there a difference in formality between ‘may’ and ‘might’?

May is generally considered slightly more formal than might, but both are used to express possibility. In many contexts, they are interchangeable. Could is also very common for possibility.

How can I practice these expressions for my B2 exam?

For B2 exams, practice using these expressions in speaking and writing tasks. For example, when asked to discuss future plans or make predictions, try to use a range of probability expressions to show nuance, such as It’s highly likely that…, I might consider…, 、または It’s very unlikely that…. Pay attention to their correct placement in sentences.